What Australian geographical feature primarily forms from sediment deposition?

The geographical feature that primarily forms from sediment deposition is the delta. Deltas are landforms that develop at the mouth of a river, where the river meets a body of water such as an ocean, sea, or lake. As the river flows, it carries sediment that is gradually deposited when the water loses energy upon entering the larger body of water. Over time, this sediment accumulation creates new land, which can expand outward from the river delta.

In contrast, a barrier reef is formed from the accumulation of coral and other organic materials rather than sediment from rivers. A coral atoll is formed around coral reefs and results from the growth of coral species over long timescales, primarily in tropical ocean waters. Mountain ranges, on the other hand, are formed through tectonic forces such as folding and faulting, not through sediment deposition. Thus, the characteristics and formation processes of deltas firmly establish them as features primarily driven by sediment deposition.